d3409d5e |
1 | /* -*-c-*- |
d3409d5e |
2 | * |
3 | * Memory management for multiprecision numbers |
4 | * |
5 | * (c) 1999 Straylight/Edgeware |
6 | */ |
7 | |
45c0fd36 |
8 | /*----- Licensing notice --------------------------------------------------* |
d3409d5e |
9 | * |
10 | * This file is part of Catacomb. |
11 | * |
12 | * Catacomb is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as |
14 | * published by the Free Software Foundation; either version 2 of the |
15 | * License, or (at your option) any later version. |
45c0fd36 |
16 | * |
d3409d5e |
17 | * Catacomb is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU Library General Public License for more details. |
45c0fd36 |
21 | * |
d3409d5e |
22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
d3409d5e |
28 | /*----- Header files ------------------------------------------------------*/ |
29 | |
d34decd2 |
30 | #include <mLib/sub.h> |
31 | |
32 | |
d3409d5e |
33 | #include "mp.h" |
34 | |
35 | /*----- Main code ---------------------------------------------------------*/ |
36 | |
d34decd2 |
37 | /* --- @mp_new@ --- * |
38 | * |
39 | * Arguments: @size_t sz@ = size of vector required |
40 | * @unsigned f@ = flags to set |
41 | * |
42 | * Returns: Pointer to a new MP structure. |
43 | * |
44 | * Use: Allocates a new multiprecision integer. The data space is |
45 | * allocated from either the standard global or secret arena, |
46 | * depending on the initial flags requested. |
47 | */ |
48 | |
49 | mp *mp_new(size_t sz, unsigned f) |
50 | { |
51 | mp *m = CREATE(mp); |
52 | m->a = (f & MP_BURN) ? MPARENA_SECURE : MPARENA_GLOBAL; |
53 | m->v = mpalloc(m->a, sz); |
54 | m->vl = m->v + sz; |
55 | m->sz = sz; |
56 | m->f = f & ~(MP_CONST | MP_DESTROYED); |
57 | m->ref = 1; |
58 | return (m); |
59 | } |
60 | |
d3409d5e |
61 | /* --- @mp_create@ --- * |
62 | * |
63 | * Arguments: @size_t sz@ = size of vector required |
64 | * |
65 | * Returns: Pointer to pristine new MP structure with enough memory |
66 | * bolted onto it. |
67 | * |
68 | * Use: Creates a new multiprecision integer, initially zero. The |
69 | * integer has a single reference. |
70 | */ |
71 | |
72 | mp *mp_create(size_t sz) |
73 | { |
74 | mp *m = CREATE(mp); |
d34decd2 |
75 | m->v = mpalloc(MPARENA_GLOBAL, sz); |
d3409d5e |
76 | m->vl = m->v + sz; |
77 | m->sz = sz; |
d34decd2 |
78 | m->a = MPARENA_GLOBAL; |
d3409d5e |
79 | m->f = MP_UNDEF; |
80 | m->ref = 1; |
81 | return (m); |
82 | } |
83 | |
d34decd2 |
84 | /* --- @mp_createsecure@ --- * |
85 | * |
86 | * Arguments: @size_t sz@ = size of vector required |
87 | * |
88 | * Returns: Pointer to pristine new MP structure with enough memory |
89 | * bolted onto it. |
90 | * |
91 | * Use: Creates a new multiprecision integer with indeterminate |
92 | * contents. The integer has a single reference. The integer's |
93 | * data space is allocated from the secure arena. Its burn flag |
94 | * is set. |
95 | */ |
96 | |
97 | mp *mp_createsecure(size_t sz) |
98 | { |
45c0fd36 |
99 | mp *m = CREATE(mp); |
d34decd2 |
100 | m->v = mpalloc(MPARENA_SECURE, sz); |
101 | m->vl = m->v + sz; |
102 | m->sz = sz; |
103 | m->a = MPARENA_SECURE; |
104 | m->f = MP_UNDEF | MP_BURN; |
105 | m->ref = 1; |
106 | return (m); |
107 | } |
108 | |
d3409d5e |
109 | /* --- @mp_build@ --- * |
110 | * |
111 | * Arguments: @mp *m@ = pointer to an MP block to fill in |
112 | * @mpw *v@ = pointer to a word array |
113 | * @mpw *vl@ = pointer just past end of array |
114 | * |
115 | * Returns: --- |
116 | * |
117 | * Use: Creates a multiprecision integer representing some smallish |
118 | * number. You must provide storage for the number and dispose |
119 | * of it when you've finished with it. The number is marked as |
120 | * constant while it exists. |
121 | */ |
122 | |
123 | void mp_build(mp *m, mpw *v, mpw *vl) |
124 | { |
125 | m->v = v; |
126 | m->vl = vl; |
127 | m->sz = vl - v; |
78ec50fa |
128 | m->a = MPARENA_GLOBAL; |
d3409d5e |
129 | m->f = MP_CONST; |
130 | m->ref = 1; |
131 | } |
132 | |
133 | /* --- @mp_destroy@ --- * |
134 | * |
135 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
136 | * |
137 | * Returns: --- |
138 | * |
139 | * Use: Destroys a multiprecision integer. The reference count isn't |
140 | * checked. Don't use this function if you don't know what |
141 | * you're doing: use @mp_drop@ instead. |
142 | */ |
143 | |
144 | void mp_destroy(mp *m) |
145 | { |
0e895689 |
146 | assert(((void)"Destroying a free integer", !(m->f & MP_DESTROYED))); |
147 | assert(((void)"Attempted to destroy a constant", !(m->f & MP_CONST))); |
d3409d5e |
148 | if (m->f & MP_BURN) |
149 | memset(m->v, 0, MPWS(m->sz)); |
d34decd2 |
150 | mpfree(m->a, m->v); |
0e895689 |
151 | m->f |= MP_DESTROYED; |
d3409d5e |
152 | DESTROY(m); |
153 | } |
154 | |
155 | /* --- @mp_copy@ --- * |
156 | * |
157 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
158 | * |
159 | * Returns: A copy of the given multiprecision integer. |
160 | * |
161 | * Use: Copies the given integer. In fact you just get another |
162 | * reference to the same old one again. |
163 | */ |
164 | |
165 | mp *mp_copy(mp *m) { return MP_COPY(m); } |
166 | |
167 | /* --- @mp_drop@ --- * |
168 | * |
169 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
170 | * |
171 | * Returns: --- |
172 | * |
173 | * Use: Drops a reference to an integer which isn't wanted any more. |
174 | * If there are no more references, the integer is destroyed. |
175 | */ |
176 | |
f1140c41 |
177 | void mp_drop(mp *m) { if (m) MP_DROP(m); } |
d3409d5e |
178 | |
179 | /* --- @mp_split@ --- * |
180 | * |
181 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
182 | * |
183 | * Returns: A reference to the same integer, possibly with a different |
184 | * address. |
185 | * |
186 | * Use: Splits off a modifiable version of the integer referred to. |
187 | */ |
188 | |
24521163 |
189 | mp *mp_split(mp *m) { MP_SPLIT(m); return (m); } |
d3409d5e |
190 | |
191 | /* --- @mp_resize@ --- * |
192 | * |
193 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
194 | * @size_t sz@ = new size |
195 | * |
196 | * Returns: --- |
197 | * |
d34decd2 |
198 | * Use: Changes an integer's size. The length and value are not |
45c0fd36 |
199 | * changed. It is an error to |
d3409d5e |
200 | */ |
201 | |
24521163 |
202 | void mp_resize(mp *m, size_t sz) { MP_RESIZE(m, sz); } |
d3409d5e |
203 | |
204 | /* --- @mp_ensure@ --- * |
205 | * |
206 | * Arguments: @mp *m@ = pointer to a multiprecision integer |
d34decd2 |
207 | * @size_t sz@ = required length |
d3409d5e |
208 | * |
209 | * Returns: --- |
210 | * |
d34decd2 |
211 | * Use: Changes an integer's length. If there is not enough space |
212 | * allocated for the new length then the size is increased. It |
d3409d5e |
213 | */ |
214 | |
24521163 |
215 | void mp_ensure(mp *m, size_t sz) { MP_ENSURE(m, sz); } |
d3409d5e |
216 | |
d34decd2 |
217 | /* --- @mp_dest@ --- * |
d3409d5e |
218 | * |
d34decd2 |
219 | * Arguments: @mp *m@ = a suggested destination integer |
220 | * @size_t sz@ = size required for result, in digits |
221 | * @unsigned f@ = various flags |
222 | * |
223 | * Returns: A pointer to an appropriate destination. |
224 | * |
225 | * Use: Converts a suggested destination into a real destination with |
226 | * the required properties. If the real destination is @d@, |
227 | * then the following properties will hold: |
d3409d5e |
228 | * |
d34decd2 |
229 | * * @d@ will have exactly one reference. |
d3409d5e |
230 | * |
d34decd2 |
231 | * * If @m@ is not @MP_NEW@, then the contents of @m@ will not |
232 | * change, unless @f@ has the @MP_UNDEF@ flag set. |
233 | * |
234 | * * If @m@ is not @MP_NEW@, then he reference count of @m@ on |
235 | * entry is equal to the sum of the counts of @d@ and @m@ on |
236 | * exit. |
237 | * |
238 | * * The size of @d@ will be at least @sz@. |
239 | * |
240 | * * If @f@ has the @MP_BURN@ flag set, then @d@ will be |
241 | * allocated from @MPARENA_SECURE@. |
242 | * |
243 | * Understanding this function is crucial to using Catacomb's |
244 | * multiprecision integer library effectively. |
d3409d5e |
245 | */ |
246 | |
d34decd2 |
247 | mp *mp_dest(mp *m, size_t sz, unsigned f) |
248 | { |
249 | /* --- If no destination, make one --- */ |
250 | |
251 | if (m == MP_NEWSEC) |
252 | m = mp_new(sz, f | MP_UNDEF | MP_BURN); |
253 | else if (m == MP_NEW) |
254 | m = mp_new(sz, f | MP_UNDEF); |
255 | else { |
256 | size_t len = MP_LEN(m); |
257 | unsigned undef = (m->f | f) & MP_UNDEF; |
258 | |
259 | /* --- If the value must be preserved, the block can't shrink --- */ |
260 | |
261 | if (!undef && sz < len) |
262 | sz = len; |
263 | |
264 | /* --- Otherwise check whether the destination is suitable --- */ |
265 | |
266 | if (m->ref > 1 || (m->f & MP_CONST) || |
53cbeae3 |
267 | sz > m->sz || ((f & ~m->f) & MP_BURN)) { |
d34decd2 |
268 | |
269 | /* --- No -- allocate a new buffer --- * |
270 | * |
271 | * The buffer must be secure if (a) the caller requested a secure |
272 | * buffer, or (b) the old buffer is secure and I'm not allowed to |
273 | * discard the old contents. |
274 | */ |
45c0fd36 |
275 | |
d34decd2 |
276 | mparena *a; |
277 | mpw *v; |
278 | |
279 | if ((f & MP_BURN) || (!undef && (m->f & MP_BURN))) |
280 | a = MPARENA_SECURE; |
281 | else |
282 | a = MPARENA_GLOBAL; |
283 | v = mpalloc(a, sz); |
284 | |
285 | /* --- Copy the data over --- */ |
286 | |
287 | if (!undef) { |
288 | memcpy(v, m->v, MPWS(len)); |
289 | if (sz - len > 0) |
290 | memset(v + len, 0, MPWS(sz - len)); |
291 | } |
292 | |
293 | /* --- If @m@ has other references, make a new node --- * |
294 | * |
295 | * Otherwise dispose of the old buffer. |
296 | */ |
297 | |
298 | if (!(m->f & MP_CONST) && m->ref == 1) { |
299 | if (m->f & MP_BURN) |
300 | memset(m->v, 0, MPWS(m->sz)); |
301 | mpfree(m->a, m->v); |
302 | } else { |
303 | mp *mm = CREATE(mp); |
304 | mm->ref = 1; |
305 | mm->f = m->f; |
306 | m->ref--; |
307 | m = mm; |
308 | } |
309 | |
310 | /* --- Fix up the node --- */ |
311 | |
312 | m->v = v; |
313 | m->vl = v + sz; |
314 | m->sz = sz; |
315 | m->f = ((m->f & ~(MP_CONST | MP_BURN)) | |
316 | (f & (MP_BURN | MP_UNDEF))); |
317 | m->a = a; |
318 | } |
319 | |
320 | /* --- If the number is growing in its buffer, fix it up --- */ |
321 | |
322 | else if (sz > len) { |
323 | if (!undef) |
324 | memset(m->vl, 0, MPWS(sz - len)); |
325 | m->vl = m->v + sz; |
326 | } |
327 | } |
328 | |
329 | /* --- Done --- */ |
330 | |
331 | return (m); |
332 | } |
d3409d5e |
333 | |
334 | /*----- That's all, folks -------------------------------------------------*/ |